This invention relates to a sewer pipe coupling. In particular, the invention relates to a sewer pipe coupling for transverse connection of a small diameter drainpipe to a structure of larger relative diameter such as a sewer pipe or maintenance chamber for accessing a mainline pipe or storm sewer catch basins.
A pipe coupling is often required when joining a pipe in transverse connection with a second pipe. When joining a drainpipe to a concrete sewer pipe, it is also desirable to provide a seal between the pipes, or between a pipe coupling and each of the two pipes to be joined. A seal may be desirable to prevent sewage from escaping and contaminating the surrounding area and also to prevent ground water from entering the sewer pipe.
Generally, a drainpipe, in transverse connection with a concrete pipe, is attached using a pipe coupling with an exterior flange for positioning. The flange extends outwardly from the coupling and abuts the exterior surface of the concrete pipe and prevents the coupling from being inserted farther into the concrete pipe.
A sealing ring, or an O-ring, on an interior surface of the pipe coupling is used for creating a seal between the coupling and an internally inserted drainpipe. The coupling is held in place in the bore-hole in the concrete pipe and sealed using cement mortar around the flange, spreading the mortar outwardly to the exterior surface of the concrete pipe. It is difficult to create a seal using mortar as it does not adhere well to the surface of the PVC pipe. Also, the mortar can shrink and crack when it dries out, thus creating a leak.
U.S. Pat. No. 6,015,169 to Funke et. al. discloses a coupling device that has an internal ring seal to create a seal with an internally located pipe and an external ring seal that abuts the concrete sewer pipe at a branch opening to create a seal. There is a flange on the outside of the pipe coupling and a separate positioning ring fits around the coupling and is located between the flange and the exterior surface of the concrete pipe. A polyurethane resin is injected between the coupling and the concrete pipe to seal and fix the coupling to the concrete pipe. This structure is somewhat complex and difficult to manufacture and install. The external stop device includes a separate positioning collar that must be inserted before the coupling is placed in the bore-hole of the pipe. Also, the device requires the injection of a polyurethane resin between the coupling and the concrete pipe.
Other couplings are available that have sealing rings or O-rings for creating a seal between a first pipe and the coupling and for creating a seal between a second pipe and the coupling. Many of these devices, however are for end-to-end connection of plastic or PVC pipes rather than for transverse connection. In U.S. Pat. No. 5,975,585 to de la Llave et al, both an internal seal and an external seal are provided in a coupling but the external seal is first positioned on the opening formed in the receiving concrete pipe. Location of the coupling in the concrete pipe is provided by an auxiliary annular element seated in a peripheral groove and location of the drain pipe inside the coupling is provided by an auxiliary stop face device. It is desirable to provide a pipe coupling for transverse connection of a drainpipe to a concrete sewer pipe and for creating a sealed connection between the coupling and each pipe which is simple and reliable to use.
There is provided a pipe connector for transverse connection of a small diameter pipe to a sewer pipe of larger relative diameter. The connector has a hollow, longitudinally extending cylindrical body with first and second ends and interior and exterior surfaces. The body has an external locating shoulder, on the exterior surface, integral with the body and extending outwardly therefrom. The external locating shoulder limits penetration of the connector in an opening in a sidewall of the large diameter pipe. The body also has an internal groove on the interior surface, located at a same longitudinal spacing as the external locating shoulder. The internal groove receives an internal sealing ring for creating a seal between the small diameter pipe and the body when the small diameter is inserted therein. The body further has an external recess on the exterior surface, longitudinally spaced from the external locating shoulder, the external recess for receiving an external sealing ring for creating a seal between the body and the large diameter pipe when the connector is inserted into the opening.